Am 22.06.2015 um 09:08 schrieb Alexandre DERUMIER <aderum...@odiso.com>:

>>> Just an update, there seems to be no proper way to pass iothread 
>>> parameter from openstack-nova (not at least in Juno release). So a 
>>> default single iothread per VM is what all we have. So in conclusion a 
>>> nova instance max iops on ceph rbd will be limited to 30-40K.
> 
> Thanks for the update.
> 
> For proxmox users, 
> 
> I have added iothread option to gui for proxmox 4.0

Can we make iothread the default? Does it also help for single disks or only 
multiple disks?

> and added jemalloc as default memory allocator
> 
> 
> I have also send a jemmaloc patch to qemu dev mailing
> https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg05265.html
> 
> (Help is welcome to push it in qemu upstream ! )
> 
> 
> 
> ----- Mail original -----
> De: "pushpesh sharma" <pushpesh....@gmail.com>
> À: "aderumier" <aderum...@odiso.com>
> Cc: "Somnath Roy" <somnath....@sandisk.com>, "Irek Fasikhov" 
> <malm...@gmail.com>, "ceph-devel" <ceph-devel@vger.kernel.org>, "ceph-users" 
> <ceph-us...@lists.ceph.com>
> Envoyé: Lundi 22 Juin 2015 07:58:47
> Objet: Re: rbd_cache, limiting read on high iops around 40k
> 
> Just an update, there seems to be no proper way to pass iothread 
> parameter from openstack-nova (not at least in Juno release). So a 
> default single iothread per VM is what all we have. So in conclusion a 
> nova instance max iops on ceph rbd will be limited to 30-40K. 
> 
> On Tue, Jun 16, 2015 at 10:08 PM, Alexandre DERUMIER 
> <aderum...@odiso.com> wrote: 
>> Hi, 
>> 
>> some news about qemu with tcmalloc vs jemmaloc. 
>> 
>> I'm testing with multiple disks (with iothreads) in 1 qemu guest. 
>> 
>> And if tcmalloc is a little faster than jemmaloc, 
>> 
>> I have hit a lot of time the tcmalloc::ThreadCache::ReleaseToCentralCache 
>> bug. 
>> 
>> increasing TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES, don't help. 
>> 
>> 
>> with multiple disk, I'm around 200k iops with tcmalloc (before hitting the 
>> bug) and 350kiops with jemmaloc. 
>> 
>> The problem is that when I hit malloc bug, I'm around 4000-10000 iops, and 
>> only way to fix is is to restart qemu ... 
>> 
>> 
>> 
>> ----- Mail original ----- 
>> De: "pushpesh sharma" <pushpesh....@gmail.com> 
>> À: "aderumier" <aderum...@odiso.com> 
>> Cc: "Somnath Roy" <somnath....@sandisk.com>, "Irek Fasikhov" 
>> <malm...@gmail.com>, "ceph-devel" <ceph-devel@vger.kernel.org>, "ceph-users" 
>> <ceph-us...@lists.ceph.com> 
>> Envoyé: Vendredi 12 Juin 2015 08:58:21 
>> Objet: Re: rbd_cache, limiting read on high iops around 40k 
>> 
>> Thanks, posted the question in openstack list. Hopefully will get some 
>> expert opinion. 
>> 
>> On Fri, Jun 12, 2015 at 11:33 AM, Alexandre DERUMIER 
>> <aderum...@odiso.com> wrote: 
>>> Hi, 
>>> 
>>> here a libvirt xml sample from libvirt src 
>>> 
>>> (you need to define <iothreads> number, then assign then in disks). 
>>> 
>>> I don't use openstack, so I really don't known how it's working with it. 
>>> 
>>> 
>>> <domain type='qemu'> 
>>> <name>QEMUGuest1</name> 
>>> <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> 
>>> <memory unit='KiB'>219136</memory> 
>>> <currentMemory unit='KiB'>219136</currentMemory> 
>>> <vcpu placement='static'>2</vcpu> 
>>> <iothreads>2</iothreads> 
>>> <os> 
>>> <type arch='i686' machine='pc'>hvm</type> 
>>> <boot dev='hd'/> 
>>> </os> 
>>> <clock offset='utc'/> 
>>> <on_poweroff>destroy</on_poweroff> 
>>> <on_reboot>restart</on_reboot> 
>>> <on_crash>destroy</on_crash> 
>>> <devices> 
>>> <emulator>/usr/bin/qemu</emulator> 
>>> <disk type='file' device='disk'> 
>>> <driver name='qemu' type='raw' iothread='1'/> 
>>> <source file='/var/lib/libvirt/images/iothrtest1.img'/> 
>>> <target dev='vdb' bus='virtio'/> 
>>> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> 
>>> </disk> 
>>> <disk type='file' device='disk'> 
>>> <driver name='qemu' type='raw' iothread='2'/> 
>>> <source file='/var/lib/libvirt/images/iothrtest2.img'/> 
>>> <target dev='vdc' bus='virtio'/> 
>>> </disk> 
>>> <controller type='usb' index='0'/> 
>>> <controller type='ide' index='0'/> 
>>> <controller type='pci' index='0' model='pci-root'/> 
>>> <memballoon model='none'/> 
>>> </devices> 
>>> </domain> 
>>> 
>>> 
>>> ----- Mail original ----- 
>>> De: "pushpesh sharma" <pushpesh....@gmail.com> 
>>> À: "aderumier" <aderum...@odiso.com> 
>>> Cc: "Somnath Roy" <somnath....@sandisk.com>, "Irek Fasikhov" 
>>> <malm...@gmail.com>, "ceph-devel" <ceph-devel@vger.kernel.org>, 
>>> "ceph-users" <ceph-us...@lists.ceph.com> 
>>> Envoyé: Vendredi 12 Juin 2015 07:52:41 
>>> Objet: Re: rbd_cache, limiting read on high iops around 40k 
>>> 
>>> Hi Alexandre, 
>>> 
>>> I agree with your rational, of one iothread per disk. CPU consumed in 
>>> IOwait is pretty high in each VM. But I am not finding a way to set 
>>> the same on a nova instance. I am using openstack Juno with QEMU+KVM. 
>>> As per libvirt documentation for setting iothreads, I can edit 
>>> domain.xml directly and achieve the same effect. However in as in 
>>> openstack env domain xml is created by nova with some additional 
>>> metadata, so editing the domain xml using 'virsh edit' does not seems 
>>> to work(I agree, it is not a very cloud way of doing things, but a 
>>> hack). Changes made there vanish after saving them, due to reason 
>>> libvirt validation fails on the same. 
>>> 
>>> #virsh dumpxml instance-000000c5 > vm.xml 
>>> #virt-xml-validate vm.xml 
>>> Relax-NG validity error : Extra element cpu in interleave 
>>> vm.xml:1: element domain: Relax-NG validity error : Element domain 
>>> failed to validate content 
>>> vm.xml fails to validate 
>>> 
>>> Second approach I took was to setting QoS in volumes types. But there 
>>> is no option to set iothreads per volume, there are parameter realted 
>>> to max_read/wrirte ops/bytes. 
>>> 
>>> Thirdly, editing Nova flavor and proving extra specs like 
>>> hw:cpu_socket/thread/core, can change guest CPU topology however again 
>>> no way to set iothread. It does accept hw_disk_iothreads(no type check 
>>> in place, i believe ), but can not pass the same in domain.xml. 
>>> 
>>> Could you suggest me a way to set the same. 
>>> 
>>> -Pushpesh 
>>> 
>>> On Wed, Jun 10, 2015 at 12:59 PM, Alexandre DERUMIER 
>>> <aderum...@odiso.com> wrote: 
>>>>>> I need to try out the performance on qemu soon and may come back to you 
>>>>>> if I need some qemu setting trick :-)
>>>> 
>>>> Sure no problem. 
>>>> 
>>>> (BTW, I can reach around 200k iops in 1 qemu vm with 5 virtio disks with 1 
>>>> iothread by disk) 
>>>> 
>>>> 
>>>> ----- Mail original ----- 
>>>> De: "Somnath Roy" <somnath....@sandisk.com> 
>>>> À: "aderumier" <aderum...@odiso.com>, "Irek Fasikhov" <malm...@gmail.com> 
>>>> Cc: "ceph-devel" <ceph-devel@vger.kernel.org>, "pushpesh sharma" 
>>>> <pushpesh....@gmail.com>, "ceph-users" <ceph-us...@lists.ceph.com> 
>>>> Envoyé: Mercredi 10 Juin 2015 09:06:32 
>>>> Objet: RE: rbd_cache, limiting read on high iops around 40k 
>>>> 
>>>> Hi Alexandre, 
>>>> Thanks for sharing the data. 
>>>> I need to try out the performance on qemu soon and may come back to you if 
>>>> I need some qemu setting trick :-) 
>>>> 
>>>> Regards 
>>>> Somnath 
>>>> 
>>>> -----Original Message----- 
>>>> From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of 
>>>> Alexandre DERUMIER 
>>>> Sent: Tuesday, June 09, 2015 10:42 PM 
>>>> To: Irek Fasikhov 
>>>> Cc: ceph-devel; pushpesh sharma; ceph-users 
>>>> Subject: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k 
>>>> 
>>>>>> Very good work! 
>>>>>> Do you have a rpm-file? 
>>>>>> Thanks.
>>>> no sorry, I'm have compiled it manually (and I'm using debian jessie as 
>>>> client) 
>>>> 
>>>> 
>>>> 
>>>> ----- Mail original ----- 
>>>> De: "Irek Fasikhov" <malm...@gmail.com> 
>>>> À: "aderumier" <aderum...@odiso.com> 
>>>> Cc: "Robert LeBlanc" <rob...@leblancnet.us>, "ceph-devel" 
>>>> <ceph-devel@vger.kernel.org>, "pushpesh sharma" <pushpesh....@gmail.com>, 
>>>> "ceph-users" <ceph-us...@lists.ceph.com> 
>>>> Envoyé: Mercredi 10 Juin 2015 07:21:42 
>>>> Objet: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k 
>>>> 
>>>> Hi, Alexandre. 
>>>> 
>>>> Very good work! 
>>>> Do you have a rpm-file? 
>>>> Thanks. 
>>>> 
>>>> 2015-06-10 7:10 GMT+03:00 Alexandre DERUMIER < aderum...@odiso.com > : 
>>>> 
>>>> 
>>>> Hi, 
>>>> 
>>>> I have tested qemu with last tcmalloc 2.4, and the improvement is huge 
>>>> with iothread: 50k iops (+45%) ! 
>>>> 
>>>> 
>>>> 
>>>> qemu : no iothread : glibc : iops=33395 qemu : no-iothread : tcmalloc 
>>>> (2.2.1) : iops=34516 (+3%) qemu : no-iothread : jemmaloc : iops=42226 
>>>> (+26%) qemu : no-iothread : tcmalloc (2.4) : iops=35974 (+7%) 
>>>> 
>>>> 
>>>> qemu : iothread : glibc : iops=34516 
>>>> qemu : iothread : tcmalloc : iops=38676 (+12%) qemu : iothread : jemmaloc 
>>>> : iops=28023 (-19%) qemu : iothread : tcmalloc (2.4) : iops=50276 (+45%) 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> qemu : iothread : tcmalloc (2.4) : iops=50276 (+45%) 
>>>> ------------------------------------------------------ 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [214.7MB/0KB/0KB /s] [54.1K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=894: Wed Jun 10 
>>>> 05:54:24 2015 read : io=5120.0MB, bw=201108KB/s, iops=50276, runt= 
>>>> 26070msec slat (usec): min=1, max=1136, avg= 3.54, stdev= 3.58 clat 
>>>> (usec): min=128, max=6262, avg=631.41, stdev=197.71 lat (usec): min=149, 
>>>> max=6265, avg=635.27, stdev=197.40 clat percentiles (usec): 
>>>> | 1.00th=[ 318], 5.00th=[ 378], 10.00th=[ 418], 20.00th=[ 474], 
>>>> | 30.00th=[ 516], 40.00th=[ 564], 50.00th=[ 612], 60.00th=[ 652], 
>>>> | 70.00th=[ 700], 80.00th=[ 756], 90.00th=[ 860], 95.00th=[ 980], 
>>>> | 99.00th=[ 1272], 99.50th=[ 1384], 99.90th=[ 1688], 99.95th=[ 1896], 
>>>> | 99.99th=[ 3760] 
>>>> bw (KB /s): min=145608, max=249688, per=100.00%, avg=201108.00, 
>>>> stdev=21718.87 lat (usec) : 250=0.04%, 500=25.84%, 750=53.00%, 1000=16.63% 
>>>> lat (msec) : 2=4.46%, 4=0.03%, 10=0.01% cpu : usr=9.73%, sys=24.93%, 
>>>> ctx=66417, majf=0, minf=38 IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 
>>>> 16=0.1%, 32=100.0%, >=64=0.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 
>>>> 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 
>>>> 32=0.1%, 64=0.0%, >=64=0.0% issued : total=r=1310720/w=0/d=0, 
>>>> short=r=0/w=0/d=0 latency : target=0, window=0, percentile=100.00%, 
>>>> depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=201107KB/s, minb=201107KB/s, maxb=201107KB/s, 
>>>> mint=26070msec, maxt=26070msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1302555/0, merge=0/0, ticks=715176/0, in_queue=714840, 
>>>> util=99.73% 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [158.7MB/0KB/0KB /s] [40.6K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=889: Wed Jun 10 
>>>> 06:05:06 2015 read : io=5120.0MB, bw=143897KB/s, iops=35974, runt= 
>>>> 36435msec slat (usec): min=1, max=710, avg= 3.31, stdev= 3.35 clat (usec): 
>>>> min=191, max=4740, avg=884.66, stdev=315.65 lat (usec): min=289, max=4743, 
>>>> avg=888.31, stdev=315.51 clat percentiles (usec): 
>>>> | 1.00th=[ 462], 5.00th=[ 516], 10.00th=[ 548], 20.00th=[ 596], 
>>>> | 30.00th=[ 652], 40.00th=[ 764], 50.00th=[ 868], 60.00th=[ 940], 
>>>> | 70.00th=[ 1004], 80.00th=[ 1096], 90.00th=[ 1256], 95.00th=[ 1416], 
>>>> | 99.00th=[ 2024], 99.50th=[ 2224], 99.90th=[ 2544], 99.95th=[ 2640], 
>>>> | 99.99th=[ 3632] 
>>>> bw (KB /s): min=98352, max=177328, per=99.91%, avg=143772.11, 
>>>> stdev=21782.39 lat (usec) : 250=0.01%, 500=3.48%, 750=35.69%, 1000=30.01% 
>>>> lat (msec) : 2=29.74%, 4=1.07%, 10=0.01% cpu : usr=7.10%, sys=16.90%, 
>>>> ctx=54855, majf=0, minf=38 IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 
>>>> 16=0.1%, 32=100.0%, >=64=0.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 
>>>> 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 
>>>> 32=0.1%, 64=0.0%, >=64=0.0% issued : total=r=1310720/w=0/d=0, 
>>>> short=r=0/w=0/d=0 latency : target=0, window=0, percentile=100.00%, 
>>>> depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=143896KB/s, minb=143896KB/s, maxb=143896KB/s, 
>>>> mint=36435msec, maxt=36435msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1301357/0, merge=0/0, ticks=1033036/0, in_queue=1032716, 
>>>> util=99.85% 
>>>> 
>>>> 
>>>> ----- Mail original ----- 
>>>> De: "aderumier" < aderum...@odiso.com > 
>>>> À: "Robert LeBlanc" < rob...@leblancnet.us > 
>>>> Cc: "Mark Nelson" < mnel...@redhat.com >, "ceph-devel" < 
>>>> ceph-devel@vger.kernel.org >, "pushpesh sharma" < pushpesh....@gmail.com 
>>>> >, "ceph-users" < ceph-us...@lists.ceph.com > 
>>>> Envoyé: Mardi 9 Juin 2015 18:47:27 
>>>> Objet: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k 
>>>> 
>>>> Hi Robert, 
>>>> 
>>>>>> What I found was that Ceph OSDs performed well with either tcmalloc or 
>>>>>> jemalloc (except when RocksDB was built with jemalloc instead of 
>>>>>> tcmalloc, I'm still working to dig into why that might be the case).
>>>> yes,from my test, for osd tcmalloc is a little faster (but very little) 
>>>> than jemalloc. 
>>>> 
>>>> 
>>>> 
>>>>>> However, I found that tcmalloc with QEMU/KVM was very detrimental to 
>>>>>> small I/O, but provided huge gains in I/O >=1MB. Jemalloc was much 
>>>>>> better for QEMU/KVM in the tests that we ran. [1]
>>>> 
>>>> 
>>>> Just have done qemu test (4k randread - rbd_cache=off), I don't see speed 
>>>> regression with tcmalloc. 
>>>> with qemu iothread, tcmalloc have a speed increase over glib 
>>>> with qemu iothread, jemalloc have a speed decrease 
>>>> 
>>>> without iothread, jemalloc have a big speed increase 
>>>> 
>>>> this is with 
>>>> -qemu 2.3 
>>>> -tcmalloc 2.2.1 
>>>> -jemmaloc 3.6 
>>>> -libc6 2.19 
>>>> 
>>>> 
>>>> qemu : no iothread : glibc : iops=33395 
>>>> qemu : no-iothread : tcmalloc : iops=34516 (+3%) 
>>>> qemu : no-iothread : jemmaloc : iops=42226 (+26%) 
>>>> 
>>>> qemu : iothread : glibc : iops=34516 
>>>> qemu : iothread : tcmalloc : iops=38676 (+12%) 
>>>> qemu : iothread : jemmaloc : iops=28023 (-19%) 
>>>> 
>>>> 
>>>> (The benefit of iothreads is that we can scale with more disks in 1vm) 
>>>> 
>>>> 
>>>> fio results: 
>>>> ------------ 
>>>> 
>>>> qemu : iothread : tcmalloc : iops=38676 
>>>> ----------------------------------------- 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=0): [r(1)] [100.0% done] [123.5MB/0KB/0KB /s] [31.6K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=1265: Tue Jun 9 
>>>> 18:16:53 2015 
>>>> read : io=5120.0MB, bw=154707KB/s, iops=38676, runt= 33889msec 
>>>> slat (usec): min=1, max=715, avg= 3.63, stdev= 3.42 
>>>> clat (usec): min=152, max=5736, avg=822.12, stdev=289.34 
>>>> lat (usec): min=231, max=5740, avg=826.10, stdev=289.08 
>>>> clat percentiles (usec): 
>>>> | 1.00th=[ 402], 5.00th=[ 466], 10.00th=[ 510], 20.00th=[ 572], 
>>>> | 30.00th=[ 636], 40.00th=[ 716], 50.00th=[ 780], 60.00th=[ 852], 
>>>> | 70.00th=[ 932], 80.00th=[ 1020], 90.00th=[ 1160], 95.00th=[ 1352], 
>>>> | 99.00th=[ 1800], 99.50th=[ 1944], 99.90th=[ 2256], 99.95th=[ 2448], 
>>>> | 99.99th=[ 3888] 
>>>> bw (KB /s): min=123888, max=198584, per=100.00%, avg=154824.40, 
>>>> stdev=16978.03 
>>>> lat (usec) : 250=0.01%, 500=8.91%, 750=36.44%, 1000=32.63% 
>>>> lat (msec) : 2=21.65%, 4=0.37%, 10=0.01% 
>>>> cpu : usr=8.29%, sys=19.76%, ctx=55882, majf=0, minf=39 
>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0% 
>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0% 
>>>> issued : total=r=1310720/w=0/d=0, short=r=0/w=0/d=0 
>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=154707KB/s, minb=154707KB/s, maxb=154707KB/s, 
>>>> mint=33889msec, maxt=33889msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1302739/0, merge=0/0, ticks=934444/0, in_queue=934096, 
>>>> util=99.77% 
>>>> 
>>>> 
>>>> 
>>>> qemu : no-iothread : tcmalloc : iops=34516 
>>>> --------------------------------------------- 
>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [163.2MB/0KB/0KB /s] [41.8K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=896: Tue Jun 9 
>>>> 18:19:08 2015 
>>>> read : io=5120.0MB, bw=138065KB/s, iops=34516, runt= 37974msec 
>>>> slat (usec): min=1, max=708, avg= 3.98, stdev= 3.57 
>>>> clat (usec): min=208, max=11858, avg=921.43, stdev=333.61 
>>>> lat (usec): min=266, max=11862, avg=925.77, stdev=333.40 
>>>> clat percentiles (usec): 
>>>> | 1.00th=[ 434], 5.00th=[ 510], 10.00th=[ 564], 20.00th=[ 652], 
>>>> | 30.00th=[ 732], 40.00th=[ 812], 50.00th=[ 876], 60.00th=[ 940], 
>>>> | 70.00th=[ 1020], 80.00th=[ 1112], 90.00th=[ 1320], 95.00th=[ 1576], 
>>>> | 99.00th=[ 1992], 99.50th=[ 2128], 99.90th=[ 2736], 99.95th=[ 3248], 
>>>> | 99.99th=[ 4320] 
>>>> bw (KB /s): min=77312, max=185576, per=99.74%, avg=137709.88, 
>>>> stdev=16883.77 
>>>> lat (usec) : 250=0.01%, 500=4.36%, 750=27.61%, 1000=35.60% 
>>>> lat (msec) : 2=31.49%, 4=0.92%, 10=0.02%, 20=0.01% 
>>>> cpu : usr=7.19%, sys=19.52%, ctx=55903, majf=0, minf=38 
>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0% 
>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0% 
>>>> issued : total=r=1310720/w=0/d=0, short=r=0/w=0/d=0 
>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=138064KB/s, minb=138064KB/s, maxb=138064KB/s, 
>>>> mint=37974msec, maxt=37974msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1309902/0, merge=0/0, ticks=1068768/0, in_queue=1068396, 
>>>> util=99.86% 
>>>> 
>>>> 
>>>> 
>>>> qemu : iothread : glibc : iops=34516 
>>>> ------------------------------------- 
>>>> 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [133.4MB/0KB/0KB /s] [34.2K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=876: Tue Jun 9 
>>>> 18:24:01 2015 
>>>> read : io=5120.0MB, bw=137786KB/s, iops=34446, runt= 38051msec 
>>>> slat (usec): min=1, max=496, avg= 3.88, stdev= 3.66 
>>>> clat (usec): min=283, max=7515, avg=923.34, stdev=300.28 
>>>> lat (usec): min=286, max=7519, avg=927.58, stdev=300.02 
>>>> clat percentiles (usec): 
>>>> | 1.00th=[ 506], 5.00th=[ 564], 10.00th=[ 596], 20.00th=[ 652], 
>>>> | 30.00th=[ 724], 40.00th=[ 804], 50.00th=[ 884], 60.00th=[ 964], 
>>>> | 70.00th=[ 1048], 80.00th=[ 1144], 90.00th=[ 1304], 95.00th=[ 1448], 
>>>> | 99.00th=[ 1896], 99.50th=[ 2096], 99.90th=[ 2480], 99.95th=[ 2640], 
>>>> | 99.99th=[ 3984] 
>>>> bw (KB /s): min=102680, max=171112, per=100.00%, avg=137877.78, 
>>>> stdev=15521.30 
>>>> lat (usec) : 500=0.84%, 750=32.97%, 1000=30.82% 
>>>> lat (msec) : 2=34.65%, 4=0.71%, 10=0.01% 
>>>> cpu : usr=7.42%, sys=19.47%, ctx=52455, majf=0, minf=38 
>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0% 
>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0% 
>>>> issued : total=r=1310720/w=0/d=0, short=r=0/w=0/d=0 
>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=137785KB/s, minb=137785KB/s, maxb=137785KB/s, 
>>>> mint=38051msec, maxt=38051msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1307426/0, merge=0/0, ticks=1051416/0, in_queue=1050972, 
>>>> util=99.85% 
>>>> 
>>>> 
>>>> 
>>>> qemu : no iothread : glibc : iops=33395 
>>>> ----------------------------------------- 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [125.4MB/0KB/0KB /s] [32.9K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=886: Tue Jun 9 
>>>> 18:27:18 2015 
>>>> read : io=5120.0MB, bw=133583KB/s, iops=33395, runt= 39248msec 
>>>> slat (usec): min=1, max=1054, avg= 3.86, stdev= 4.29 
>>>> clat (usec): min=139, max=12635, avg=952.85, stdev=335.51 
>>>> lat (usec): min=303, max=12638, avg=957.01, stdev=335.29 
>>>> clat percentiles (usec): 
>>>> | 1.00th=[ 516], 5.00th=[ 564], 10.00th=[ 596], 20.00th=[ 652], 
>>>> | 30.00th=[ 724], 40.00th=[ 820], 50.00th=[ 924], 60.00th=[ 996], 
>>>> | 70.00th=[ 1080], 80.00th=[ 1176], 90.00th=[ 1336], 95.00th=[ 1528], 
>>>> | 99.00th=[ 2096], 99.50th=[ 2320], 99.90th=[ 2672], 99.95th=[ 2928], 
>>>> | 99.99th=[ 4832] 
>>>> bw (KB /s): min=98136, max=171624, per=100.00%, avg=133682.64, 
>>>> stdev=19121.91 
>>>> lat (usec) : 250=0.01%, 500=0.57%, 750=32.57%, 1000=26.98% 
>>>> lat (msec) : 2=38.59%, 4=1.28%, 10=0.01%, 20=0.01% 
>>>> cpu : usr=9.24%, sys=15.92%, ctx=51219, majf=0, minf=38 
>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0% 
>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0% 
>>>> issued : total=r=1310720/w=0/d=0, short=r=0/w=0/d=0 
>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=133583KB/s, minb=133583KB/s, maxb=133583KB/s, 
>>>> mint=39248msec, maxt=39248msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1304526/0, merge=0/0, ticks=1075020/0, in_queue=1074536, 
>>>> util=99.84% 
>>>> 
>>>> 
>>>> 
>>>> qemu : iothread : jemmaloc : iops=28023 
>>>> ---------------------------------------- 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=1): [r(1)] [97.9% done] [155.2MB/0KB/0KB /s] [39.1K/0/0 iops] 
>>>> [eta 00m:01s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=899: Tue Jun 9 
>>>> 18:30:26 2015 
>>>> read : io=5120.0MB, bw=112094KB/s, iops=28023, runt= 46772msec 
>>>> slat (usec): min=1, max=467, avg= 4.33, stdev= 4.77 
>>>> clat (usec): min=253, max=11307, avg=1135.63, stdev=346.55 
>>>> lat (usec): min=256, max=11309, avg=1140.39, stdev=346.22 
>>>> clat percentiles (usec): 
>>>> | 1.00th=[ 510], 5.00th=[ 628], 10.00th=[ 700], 20.00th=[ 820], 
>>>> | 30.00th=[ 924], 40.00th=[ 1032], 50.00th=[ 1128], 60.00th=[ 1224], 
>>>> | 70.00th=[ 1320], 80.00th=[ 1416], 90.00th=[ 1560], 95.00th=[ 1688], 
>>>> | 99.00th=[ 2096], 99.50th=[ 2224], 99.90th=[ 2544], 99.95th=[ 2832], 
>>>> | 99.99th=[ 3760] 
>>>> bw (KB /s): min=91792, max=174416, per=99.90%, avg=111985.27, 
>>>> stdev=17381.70 
>>>> lat (usec) : 500=0.80%, 750=13.10%, 1000=23.33% 
>>>> lat (msec) : 2=61.30%, 4=1.46%, 10=0.01%, 20=0.01% 
>>>> cpu : usr=7.12%, sys=17.43%, ctx=54507, majf=0, minf=38 
>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0% 
>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0% 
>>>> issued : total=r=1310720/w=0/d=0, short=r=0/w=0/d=0 
>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=112094KB/s, minb=112094KB/s, maxb=112094KB/s, 
>>>> mint=46772msec, maxt=46772msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1309169/0, merge=0/0, ticks=1305796/0, in_queue=1305376, 
>>>> util=98.68% 
>>>> 
>>>> 
>>>> 
>>>> qemu : non-iothread : jemmaloc : iops=42226 
>>>> -------------------------------------------- 
>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>> ioengine=libaio, iodepth=32 
>>>> fio-2.1.11 
>>>> Starting 1 process 
>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [171.2MB/0KB/0KB /s] [43.9K/0/0 iops] 
>>>> [eta 00m:00s] 
>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=892: Tue Jun 9 
>>>> 18:34:11 2015 
>>>> read : io=5120.0MB, bw=177130KB/s, iops=44282, runt= 29599msec 
>>>> slat (usec): min=1, max=527, avg= 3.80, stdev= 3.74 
>>>> clat (usec): min=174, max=3841, avg=717.08, stdev=237.53 
>>>> lat (usec): min=210, max=3844, avg=721.23, stdev=237.22 
>>>> clat percentiles (usec): 
>>>> | 1.00th=[ 354], 5.00th=[ 422], 10.00th=[ 462], 20.00th=[ 516], 
>>>> | 30.00th=[ 572], 40.00th=[ 628], 50.00th=[ 684], 60.00th=[ 740], 
>>>> | 70.00th=[ 804], 80.00th=[ 884], 90.00th=[ 1004], 95.00th=[ 1128], 
>>>> | 99.00th=[ 1544], 99.50th=[ 1672], 99.90th=[ 1928], 99.95th=[ 2064], 
>>>> | 99.99th=[ 2608] 
>>>> bw (KB /s): min=138120, max=230816, per=100.00%, avg=177192.14, 
>>>> stdev=23440.79 
>>>> lat (usec) : 250=0.01%, 500=16.24%, 750=45.93%, 1000=27.46% 
>>>> lat (msec) : 2=10.30%, 4=0.07% 
>>>> cpu : usr=10.14%, sys=23.84%, ctx=60938, majf=0, minf=39 
>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=64=0.0% 
>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0% 
>>>> issued : total=r=1310720/w=0/d=0, short=r=0/w=0/d=0 
>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>> 
>>>> Run status group 0 (all jobs): 
>>>> READ: io=5120.0MB, aggrb=177130KB/s, minb=177130KB/s, maxb=177130KB/s, 
>>>> mint=29599msec, maxt=29599msec 
>>>> 
>>>> Disk stats (read/write): 
>>>> vdb: ios=1303992/0, merge=0/0, ticks=798008/0, in_queue=797636, 
>>>> util=99.80% 
>>>> 
>>>> 
>>>> 
>>>> ----- Mail original ----- 
>>>> De: "Robert LeBlanc" < rob...@leblancnet.us > 
>>>> À: "aderumier" < aderum...@odiso.com > 
>>>> Cc: "Mark Nelson" < mnel...@redhat.com >, "ceph-devel" < 
>>>> ceph-devel@vger.kernel.org >, "pushpesh sharma" < pushpesh....@gmail.com 
>>>> >, "ceph-users" < ceph-us...@lists.ceph.com > 
>>>> Envoyé: Mardi 9 Juin 2015 18:00:29 
>>>> Objet: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k 
>>>> 
>>>> -----BEGIN PGP SIGNED MESSAGE----- 
>>>> Hash: SHA256 
>>>> 
>>>> I also saw a similar performance increase by using alternative memory 
>>>> allocators. What I found was that Ceph OSDs performed well with either 
>>>> tcmalloc or jemalloc (except when RocksDB was built with jemalloc 
>>>> instead of tcmalloc, I'm still working to dig into why that might be 
>>>> the case). 
>>>> 
>>>> However, I found that tcmalloc with QEMU/KVM was very detrimental to 
>>>> small I/O, but provided huge gains in I/O >=1MB. Jemalloc was much 
>>>> better for QEMU/KVM in the tests that we ran. [1] 
>>>> 
>>>> I'm currently looking into I/O bottlenecks around the 16KB range and 
>>>> I'm seeing a lot of time in thread creation and destruction, the 
>>>> memory allocators are quite a bit down the list (both fio with 
>>>> ioengine rbd and on the OSDs). I wonder what the difference can be. 
>>>> I've tried using the async messenger but there wasn't a huge 
>>>> difference. [2] 
>>>> 
>>>> Further down the rabbit hole.... 
>>>> 
>>>> [1] https://www.mail-archive.com/ceph-users@lists.ceph.com/msg20197.html 
>>>> [2] https://www.mail-archive.com/ceph-devel@vger.kernel.org/msg23982.html 
>>>> -----BEGIN PGP SIGNATURE----- 
>>>> Version: Mailvelope v0.13.1 
>>>> Comment: https://www.mailvelope.com 
>>>> 
>>>> wsFcBAEBCAAQBQJVdw2ZCRDmVDuy+mK58QAA4MwP/1vt65cvTyyVGGSGRrE8 
>>>> unuWjafMHzl486XH+EaVrDVTXFVFOoncJ6kugSpD7yavtCpZNdhsIaTRZguU 
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>>>> R+v6wxhQU0vBovH+5oAWmCZaPNT+F0Uvs3xWAxxaIR9r83wMj9qQeBZTKVzQ 
>>>> 1aFIi15KqAwOp12yWCmrqKTeXhjwYQNd8viCQCGN7AQyPglmzfbuEHalVjz4 
>>>> oSJX 
>>>> =k281 
>>>> -----END PGP SIGNATURE----- 
>>>> ---------------- 
>>>> Robert LeBlanc 
>>>> GPG Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 
>>>> 
>>>> 
>>>> On Tue, Jun 9, 2015 at 6:02 AM, Alexandre DERUMIER < aderum...@odiso.com > 
>>>> wrote: 
>>>>>>> Frankly, I'm a little impressed that without RBD cache we can hit 80K 
>>>>>>> IOPS from 1 VM!
>>>>> 
>>>>> Note that theses result are not in a vm (fio-rbd on host), so in a vm 
>>>>> we'll have overhead. 
>>>>> (I'm planning to send results in qemu soon) 
>>>>> 
>>>>>>> How fast are the SSDs in those 3 OSDs?
>>>>> 
>>>>> Theses results are with datas in buffer memory of osd nodes. 
>>>>> 
>>>>> When reading fulling on ssd (intel s3500), 
>>>>> 
>>>>> For 1 client, 
>>>>> 
>>>>> I'm around 33k iops without cache and 32k iops with cache, with 1 osd. 
>>>>> I'm around 55k iops without cache and 38k iops with cache, with 3 osd. 
>>>>> 
>>>>> with multiple clients jobs, I can reach around 70kiops by osd , and 250k 
>>>>> iops by osd when datas are in buffer. 
>>>>> 
>>>>> (cpus servers/clients are 2x 10 cores 3,1ghz e5 xeon) 
>>>>> 
>>>>> 
>>>>> 
>>>>> small tip : 
>>>>> I'm using tcmalloc for fio-rbd or rados bench to improve latencies by 
>>>>> around 20% 
>>>>> 
>>>>> LD_PRELOAD=/usr/lib/libtcmalloc_minimal.so.4 fio ... 
>>>>> LD_PRELOAD=/usr/lib/libtcmalloc_minimal.so.4 rados bench ... 
>>>>> 
>>>>> as a lot of time is spent in malloc/free 
>>>>> 
>>>>> 
>>>>> (qemu support also tcmalloc since some months , I'll bench it too 
>>>>> https://lists.gnu.org/archive/html/qemu-devel/2015-03/msg05372.html ) 
>>>>> 
>>>>> 
>>>>> 
>>>>> I'll try to send full bench results soon, from 1 to 18 ssd osd. 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> ----- Mail original ----- 
>>>>> De: "Mark Nelson" < mnel...@redhat.com > 
>>>>> À: "aderumier" < aderum...@odiso.com >, "pushpesh sharma" < 
>>>>> pushpesh....@gmail.com > 
>>>>> Cc: "ceph-devel" < ceph-devel@vger.kernel.org >, "ceph-users" < 
>>>>> ceph-us...@lists.ceph.com > 
>>>>> Envoyé: Mardi 9 Juin 2015 13:36:31 
>>>>> Objet: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k 
>>>>> 
>>>>> Hi All, 
>>>>> 
>>>>> In the past we've hit some performance issues with RBD cache that we've 
>>>>> fixed, but we've never really tried pushing a single VM beyond 40+K read 
>>>>> IOPS in testing (or at least I never have). I suspect there's a couple 
>>>>> of possibilities as to why it might be slower, but perhaps joshd can 
>>>>> chime in as he's more familiar with what that code looks like. 
>>>>> 
>>>>> Frankly, I'm a little impressed that without RBD cache we can hit 80K 
>>>>> IOPS from 1 VM! How fast are the SSDs in those 3 OSDs? 
>>>>> 
>>>>> Mark 
>>>>> 
>>>>>> On 06/09/2015 03:36 AM, Alexandre DERUMIER wrote: 
>>>>>> It's seem that the limit is mainly going in high queue depth (+- > 16) 
>>>>>> 
>>>>>> Here the result in iops with 1client- 4krandread- 3osd - with differents 
>>>>>> queue depth size. 
>>>>>> rbd_cache is almost the same than without cache with queue depth <16 
>>>>>> 
>>>>>> 
>>>>>> cache 
>>>>>> ----- 
>>>>>> qd1: 1651 
>>>>>> qd2: 3482 
>>>>>> qd4: 7958 
>>>>>> qd8: 17912 
>>>>>> qd16: 36020 
>>>>>> qd32: 42765 
>>>>>> qd64: 46169 
>>>>>> 
>>>>>> no cache 
>>>>>> -------- 
>>>>>> qd1: 1748 
>>>>>> qd2: 3570 
>>>>>> qd4: 8356 
>>>>>> qd8: 17732 
>>>>>> qd16: 41396 
>>>>>> qd32: 78633 
>>>>>> qd64: 79063 
>>>>>> qd128: 79550 
>>>>>> 
>>>>>> 
>>>>>> ----- Mail original ----- 
>>>>>> De: "aderumier" < aderum...@odiso.com > 
>>>>>> À: "pushpesh sharma" < pushpesh....@gmail.com > 
>>>>>> Cc: "ceph-devel" < ceph-devel@vger.kernel.org >, "ceph-users" < 
>>>>>> ceph-us...@lists.ceph.com > 
>>>>>> Envoyé: Mardi 9 Juin 2015 09:28:21 
>>>>>> Objet: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k 
>>>>>> 
>>>>>> Hi, 
>>>>>> 
>>>>>>>> We tried adding more RBDs to single VM, but no luck.
>>>>>> 
>>>>>> If you want to scale with more disks in a single qemu vm, you need to 
>>>>>> use iothread feature from qemu and assign 1 iothread by disk (works with 
>>>>>> virtio-blk). 
>>>>>> It's working for me, I can scale with adding more disks. 
>>>>>> 
>>>>>> 
>>>>>> My bench here are done with fio-rbd on host. 
>>>>>> I can scale up to 400k iops with 10clients-rbd_cache=off on a single 
>>>>>> host and around 250kiops 10clients-rbdcache=on. 
>>>>>> 
>>>>>> 
>>>>>> I just wonder why I don't have performance decrease around 30k iops with 
>>>>>> 1osd. 
>>>>>> 
>>>>>> I'm going to see if this tracker 
>>>>>> http://tracker.ceph.com/issues/11056 
>>>>>> 
>>>>>> could be the cause. 
>>>>>> 
>>>>>> (My master build was done some week ago) 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> ----- Mail original ----- 
>>>>>> De: "pushpesh sharma" < pushpesh....@gmail.com > 
>>>>>> À: "aderumier" < aderum...@odiso.com > 
>>>>>> Cc: "ceph-devel" < ceph-devel@vger.kernel.org >, "ceph-users" < 
>>>>>> ceph-us...@lists.ceph.com > 
>>>>>> Envoyé: Mardi 9 Juin 2015 09:21:04 
>>>>>> Objet: Re: rbd_cache, limiting read on high iops around 40k 
>>>>>> 
>>>>>> Hi Alexandre, 
>>>>>> 
>>>>>> We have also seen something very similar on Hammer(0.94-1). We were 
>>>>>> doing some benchmarking for VMs hosted on hypervisor (QEMU-KVM, 
>>>>>> openstack-juno). Each Ubuntu-VM has a RBD as root disk, and 1 RBD as 
>>>>>> additional storage. For some strange reason it was not able to scale 4K- 
>>>>>> RR iops on each VM beyond 35-40k. We tried adding more RBDs to single 
>>>>>> VM, but no luck. However increasing number of VMs to 4 on a single 
>>>>>> hypervisor did scale to some extent. After this there was no much 
>>>>>> benefit we got from adding more VMs. 
>>>>>> 
>>>>>> Here is the trend we have seen, x-axis is number of hypervisor, each 
>>>>>> hypervisor has 4 VM, each VM has 1 RBD:- 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> VDbench is used as benchmarking tool. We were not saturating network and 
>>>>>> CPUs at OSD nodes. We were not able to saturate CPUs at hypervisors, and 
>>>>>> that is where we were suspecting of some throttling effect. However we 
>>>>>> haven't setted any such limits from nova or kvm end. We tried some CPU 
>>>>>> pinning and other KVM related tuning as well, but no luck. 
>>>>>> 
>>>>>> We tried the same experiment on a bare metal. It was 4K RR IOPs were 
>>>>>> scaling from 40K(1 RBD) to 180K(4 RBDs). But after that rather than 
>>>>>> scaling beyond that point the numbers were actually degrading. (Single 
>>>>>> pipe more congestion effect) 
>>>>>> 
>>>>>> We never suspected that rbd cache enable could be detrimental to 
>>>>>> performance. It would nice to route cause the problem if that is the 
>>>>>> case. 
>>>>>> 
>>>>>> On Tue, Jun 9, 2015 at 11:21 AM, Alexandre DERUMIER < 
>>>>>> aderum...@odiso.com > wrote: 
>>>>>> 
>>>>>> 
>>>>>> Hi, 
>>>>>> 
>>>>>> I'm doing benchmark (ceph master branch), with randread 4k qdepth=32, 
>>>>>> and rbd_cache=true seem to limit the iops around 40k 
>>>>>> 
>>>>>> 
>>>>>> no cache 
>>>>>> -------- 
>>>>>> 1 client - rbd_cache=false - 1osd : 38300 iops 
>>>>>> 1 client - rbd_cache=false - 2osd : 69073 iops 
>>>>>> 1 client - rbd_cache=false - 3osd : 78292 iops 
>>>>>> 
>>>>>> 
>>>>>> cache 
>>>>>> ----- 
>>>>>> 1 client - rbd_cache=true - 1osd : 38100 iops 
>>>>>> 1 client - rbd_cache=true - 2osd : 42457 iops 
>>>>>> 1 client - rbd_cache=true - 3osd : 45823 iops 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> Is it expected ? 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> fio result rbd_cache=false 3 osd 
>>>>>> -------------------------------- 
>>>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>>>> ioengine=rbd, iodepth=32 
>>>>>> fio-2.1.11 
>>>>>> Starting 1 process 
>>>>>> rbd engine: RBD version: 0.1.9 
>>>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [307.5MB/0KB/0KB /s] [78.8K/0/0 
>>>>>> iops] [eta 00m:00s] 
>>>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=113548: Tue Jun 9 
>>>>>> 07:48:42 2015 
>>>>>> read : io=10000MB, bw=313169KB/s, iops=78292, runt= 32698msec 
>>>>>> slat (usec): min=5, max=530, avg=11.77, stdev= 6.77 
>>>>>> clat (usec): min=70, max=2240, avg=336.08, stdev=94.82 
>>>>>> lat (usec): min=101, max=2247, avg=347.84, stdev=95.49 
>>>>>> clat percentiles (usec): 
>>>>>> | 1.00th=[ 173], 5.00th=[ 209], 10.00th=[ 231], 20.00th=[ 262], 
>>>>>> | 30.00th=[ 282], 40.00th=[ 302], 50.00th=[ 322], 60.00th=[ 346], 
>>>>>> | 70.00th=[ 370], 80.00th=[ 402], 90.00th=[ 454], 95.00th=[ 506], 
>>>>>> | 99.00th=[ 628], 99.50th=[ 692], 99.90th=[ 860], 99.95th=[ 948], 
>>>>>> | 99.99th=[ 1176] 
>>>>>> bw (KB /s): min=238856, max=360448, per=100.00%, avg=313402.34, 
>>>>>> stdev=25196.21 
>>>>>> lat (usec) : 100=0.01%, 250=15.94%, 500=78.60%, 750=5.19%, 1000=0.23% 
>>>>>> lat (msec) : 2=0.03%, 4=0.01% 
>>>>>> cpu : usr=74.48%, sys=13.25%, ctx=703225, majf=0, minf=12452 
>>>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.8%, 16=87.0%, 32=12.1%, 
>>>>>> >=64=0.0% 
>>>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>>>> complete : 0=0.0%, 4=91.6%, 8=3.4%, 16=4.5%, 32=0.4%, 64=0.0%, >=64=0.0% 
>>>>>> issued : total=r=2560000/w=0/d=0, short=r=0/w=0/d=0 
>>>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>>>> 
>>>>>> Run status group 0 (all jobs): 
>>>>>> READ: io=10000MB, aggrb=313169KB/s, minb=313169KB/s, maxb=313169KB/s, 
>>>>>> mint=32698msec, maxt=32698msec 
>>>>>> 
>>>>>> Disk stats (read/write): 
>>>>>> dm-0: ios=0/45, merge=0/0, ticks=0/0, in_queue=0, util=0.00%, 
>>>>>> aggrios=0/24, aggrmerge=0/21, aggrticks=0/0, aggrin_queue=0, 
>>>>>> aggrutil=0.00% 
>>>>>> sda: ios=0/24, merge=0/21, ticks=0/0, in_queue=0, util=0.00% 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> fio result rbd_cache=true 3osd 
>>>>>> ------------------------------ 
>>>>>> 
>>>>>> rbd_iodepth32-test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, 
>>>>>> ioengine=rbd, iodepth=32 
>>>>>> fio-2.1.11 
>>>>>> Starting 1 process 
>>>>>> rbd engine: RBD version: 0.1.9 
>>>>>> Jobs: 1 (f=1): [r(1)] [100.0% done] [171.6MB/0KB/0KB /s] [43.1K/0/0 
>>>>>> iops] [eta 00m:00s] 
>>>>>> rbd_iodepth32-test: (groupid=0, jobs=1): err= 0: pid=113389: Tue Jun 9 
>>>>>> 07:47:30 2015 
>>>>>> read : io=10000MB, bw=183296KB/s, iops=45823, runt= 55866msec 
>>>>>> slat (usec): min=7, max=805, avg=21.26, stdev=15.84 
>>>>>> clat (usec): min=101, max=4602, avg=478.55, stdev=143.73 
>>>>>> lat (usec): min=123, max=4669, avg=499.80, stdev=146.03 
>>>>>> clat percentiles (usec): 
>>>>>> | 1.00th=[ 227], 5.00th=[ 274], 10.00th=[ 306], 20.00th=[ 350], 
>>>>>> | 30.00th=[ 390], 40.00th=[ 430], 50.00th=[ 470], 60.00th=[ 506], 
>>>>>> | 70.00th=[ 548], 80.00th=[ 596], 90.00th=[ 660], 95.00th=[ 724], 
>>>>>> | 99.00th=[ 844], 99.50th=[ 908], 99.90th=[ 1112], 99.95th=[ 1288], 
>>>>>> | 99.99th=[ 2192] 
>>>>>> bw (KB /s): min=115280, max=204416, per=100.00%, avg=183315.10, 
>>>>>> stdev=15079.93 
>>>>>> lat (usec) : 250=2.42%, 500=55.61%, 750=38.48%, 1000=3.28% 
>>>>>> lat (msec) : 2=0.19%, 4=0.01%, 10=0.01% 
>>>>>> cpu : usr=60.27%, sys=12.01%, ctx=2995393, majf=0, minf=14100 
>>>>>> IO depths : 1=0.1%, 2=0.1%, 4=0.2%, 8=13.5%, 16=81.0%, 32=5.3%, 
>>>>>> >=64=0.0% 
>>>>>> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% 
>>>>>> complete : 0=0.0%, 4=95.0%, 8=0.1%, 16=1.0%, 32=4.0%, 64=0.0%, >=64=0.0% 
>>>>>> issued : total=r=2560000/w=0/d=0, short=r=0/w=0/d=0 
>>>>>> latency : target=0, window=0, percentile=100.00%, depth=32 
>>>>>> 
>>>>>> Run status group 0 (all jobs): 
>>>>>> READ: io=10000MB, aggrb=183295KB/s, minb=183295KB/s, maxb=183295KB/s, 
>>>>>> mint=55866msec, maxt=55866msec 
>>>>>> 
>>>>>> Disk stats (read/write): 
>>>>>> dm-0: ios=0/61, merge=0/0, ticks=0/8, in_queue=8, util=0.01%, 
>>>>>> aggrios=0/29, aggrmerge=0/32, aggrticks=0/8, aggrin_queue=8, 
>>>>>> aggrutil=0.01% 
>>>>>> sda: ios=0/29, merge=0/32, ticks=0/8, in_queue=8, util=0.01%
>>>>> _______________________________________________ 
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>>>> 
>>>> 
>>>> -- 
>>>> С уважением, Фасихов Ирек Нургаязович 
>>>> Моб.: +79229045757 
>>>> _______________________________________________ 
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>>> -- 
>>> -Pushpesh
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>> -Pushpesh
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